Czech Journal of Food Sciences, 2002 (vol. 20), issue 4

Changes of wheat flour properties during short term storage

M. Hrušková, D. Machová

Czech J. Food Sci., 2002, 20(4):125-130 | DOI: 10.17221/3522-CJFS  

Two samples of commercial wheat flour from the last year's harvest were stored for three months (in the period from November to April) under different conditions. The ambient temperature and humidity varied during the storage in the dependence on the year season. Certain analytical characteristics (moisture, wet gluten and its extensibility, acidity and falling number) and alveograph behaviour of flour were determined at regular intervals. Flour moisture, acidity, and falling number changed with the time of storage but no explicit influence of the storehouse conditions and the initial flour properties was proved. Viscoelastic properties of weaker flour...

Comparison of some commercial pectic enzyme preparations applicable in wine technology

D. Čapounová, M. Drdák

Czech J. Food Sci., 2002, 20(4):131-134 | DOI: 10.17221/3523-CJFS  

The preparations of pectic enzymes are used for a more efficient extraction of desirable red grape pigments and other phenol compounds which are bound in plant cells and can be faster released by the action of pectic enzymes. Moreover, they shorten the time of maceration, settling, and filtration. The results of our experiments gives a comparison of the efficiency of preparations applicable in wine technology. The best preparation was Trenolin Rot followed by Vinozym G that could shorten the time of prefermentation to about 3 days thanks to a more intensive extraction of red grape pigments. By using the enzyme preparations Gammapect AWP and Ovopres,...

The use of PCA, FA, CA for the evaluation of vegetable juices processed by lactic acid fermentation

J. Karovičová, Z. Kohajdová

Czech J. Food Sci., 2002, 20(4):135-143 | DOI: 10.17221/3524-CJFS  

The cabbage-carrot juices were inoculated with Lactobacillus plantarum 92H at the concentration of 8 × 106 CFU/ml and fermented in a thermostat at 24°C for 150 hours. During the fermentation, both analytical (pH, total acidity, reducing sugars, l-ascorbic acid, lactic, acetic and citric acids, biogenic amines) and sensory (appearance, colour, turbidity, sediment and taste) parameters were followed. For the evaluation of the results of the chemical and sensory (taste) analyses of these juices the multivariate statistical methods were applied. PCA and FA reduced the 7 original analytical variables to 1 independent component (factor) that accounted...

Lipid oxidation and quality parameters of sausages marketed locally in the town of Săo Paulo (Brazil)

C.K.B. Ferrari, E.A.F.S. Torres

Czech J. Food Sci., 2002, 20(4):144-150 | DOI: 10.17221/3525-CJFS  

Lipid oxidation constitutes one of the most important causes of the chemical deterioration of foods, especially meats. Many harmful effects on human health are associated with lipid oxidation. During a period of six weeks, samples were bought at random on city hall food markets (CHFMs) and were analysed for lipid oxidation (TBARS-test) and some quality factors - redox potential (Eh), pH and water activity (aw). The mean of Eh was X ± σn-1 = 39.03 ± 26.30 mV, ranging from -86.00 to 92.00 mV. pH mean value was X ± σn-1 = 5.97 ± 0.27, ranging from 5.08 to 6.48. Comparing...

Temperature profiles in dough products during microwave heating with susceptors

J. Houšová, K. Hoke

Czech J. Food Sci., 2002, 20(4):151-160 | DOI: 10.17221/3526-CJFS  

The effect of food products on temperatures reached in the microwave heating with and without susceptors was followed in experiments with certain types of food samples. A household microwave oven (650 W), susceptors from commercial packages for microwave popcorn, samples of two commercial pizza products and two types of dough were used in the experiments together with Luxtron temperature measurement system. The temperatures reached at the end of heating on the bottom surface of samples varied between 103 and 115°C at the heating without susceptor, and between 110 and 155°C at the heating with susceptor. Not only the susceptor but also the parameters...